Letter Cite This: ACS Macro Lett. 2018, 7, 651−655
pubs.acs.org/macroletters
In Situ Water-Compatible Polymer Entrapment: A Strategy for Transferring Superhydrophobic Microporous Organic Polymers to Water Doo Hun Lee,†,∥ Kyoung Chul Ko,†,∥ Ju Hong Ko,† Shin Young Kang,† Sang Moon Lee,‡ Hae Jin Kim,‡ Yoon-Joo Ko,§ Jin Yong Lee,*,† and Seung Uk Son*,† †
Department of Chemistry, Sungkyunkwan University, Suwon 16419, Korea Korea Basic Science Institute, Daejeon 34133, Korea § Laboratory of Nuclear Magnetic Resonance, National Center for Inter-University Research Facilities (NCIRF), Seoul National University, Seoul 08826, Korea ‡
S Supporting Information *
ABSTRACT: Microporous organic polymer nanoparticles bearing tetraphenylethylene moieties (MOPTs) were prepared in the presence of poly(vinylpyrrolidone) (PVP). The PVP was entrapped into the microporous network of MOPT to form MOPT-P and played the roles of size control, porosity enhancement, and surface property management. MOPT materials without PVP showed superhydrophobicity with a water contact angle of 151°. In comparison, the MOPT-P showed excellent water compatibility. Moreover, due to the aggregation-induced emission property of tetraphenylethylene moieties, the MOPT-P showed emission and excellent emission-based sensing of nitrophenols in water with Ksv values in the range of 1.26 × 104 ∼ 3.37 × 104 M−1. It is noteworthy that the MOPT-P used water only as a sensing medium and did not require additional organic solvents to enhance water dispersibility of materials. The MOPT-P could be recovered and reused for the sensing at least five times.
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Emissive MOPs have been applied for the sensing of water pollutants.13−23 However, due to the unique organic nature of MOPs, additional water-compatible organic solvents such as tetrahydrofuran, acetonitrile, and ethanol have been added to original aqueous systems. Thus, to avoid using the potentially harmful organic solvents, more synthetic efforts for watercompatible MOPs are required. The surfactants such as cetyltrimethylammonium bromide or sodium dodecyl sulfate were introduced to enhance the dispersibility of MOP materials in water.24−27 Recently, we applied MOPs as seed materials for the synthesis of polyketones and discovered that linear polymers can be entrapped into the microporous network of MOPs.28,29 Thus, we thought that water-soluble polymers such as poly(vinylpyrrolidone) (PVP) can be introduced into the MOPs to realize water-compatible MOPs. Aggregation-induced emission (AIE) has attracted considerable attention of scientists as a useful phenomenon.30,31 For a typical example, tetraphenylethylene moieties have shown the AIE properties.30,31 Based on these AIE properties, various functional organic materials including sensing materials have been developed.30−34 Recently, the emission properties of the MOPs including tetraphenylethylene-based ones have been studied.35−38 As shown in the control experiments in Figure 1,
ecently, organic polymers with microporosity (pore sizes
